diff -ruN a/tar b/tar
--- a/tar	2010-09-03 14:43:54.159421877 +0200
+++ b/tar	2010-09-03 14:40:50.522840422 +0200
@@ -19,7 +19,7 @@
         return 0
         ;;
     +([^IZzJjy])f)
-        ext='t@(ar?(.@(Z|gz|bz?(2)|lz?(ma)))|gz|bz?(2)|lz?(ma))'
+        ext='t@(ar?(.@(Z|gz|bz?(2)|lz?(ma)|xz))|gz|bz?(2)|lz?(ma)|xz)'
         regex='t\(ar\(\.\(Z\|gz\|bz2\?\|lzma\|xz\)\)\?\|gz\|bz2\?\|lzma\|xz\)'
         ;;
     *[Zz]*f)